A Peer-to-Peer Recommender System Based on Spontaneous Affinities

Network analysis has proved to be very useful in many social and natural sciences, and in particular Small World topologies have been exploited in many application fields. In this article, we focus on P2P file sharing applications, where spontaneous communities of users are studied and analyzed. We define a family of structures that we call "Affinity Networks" (or even Graphs) that show self-organized interest-based clusters. Empirical evidence proves that affinity networks are small worlds and shows scale-free features. The relevance of this finding is augmented with the introduction of a proactive recommendation scheme, namely DeHinter, that exploits this natural feature. The intuition behind this scheme is that a user would trust her network of "elective affinities" more than anonymous and generic suggestions made by impersonal entities. The accuracy of the recommendation is evaluated by way of a 10-fold cross validation, and a prototype has been implemented for further feedbacks from the users.